\Header{coef.lmList}{Extract lmList Coefficients}
\keyword{models}{coef.lmList}
\begin{Description}\relax
The coefficients of each \code{lm} object in the \code{object} list are
extracted and organized into a data frame, with rows corresponding to
the \code{lm} components and columns corresponding to the
coefficients.  Optionally, the returned data frame may be augmented
with covariates summarized over the groups associated with the
\code{lm} components.\end{Description}
\begin{Usage}
\begin{verbatim}
## S3 method for class 'lmList':
coef(object, augFrame, data, which, FUN,
   omitGroupingFactor, ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{object}] an object inheriting from class \code{lmList}, representing
a list of \code{lm} objects with a common model.

\item[\code{augFrame}] an optional logical value. If \code{TRUE}, the returned
data frame is augmented with variables defined in the data frame used
to produce \code{object}; else, if \code{FALSE}, only the coefficients
are returned. Defaults to \code{FALSE}.

\item[\code{data}] an optional data frame with the variables to be used for
augmenting the returned data frame when \code{augFrame =
     TRUE}. Defaults to the data frame used to fit \code{object}.
\item[\code{which}] an optional positive integer or character vector
specifying which columns of the data frame used to produce \code{object}
should be used in the augmentation of the returned data
frame. Defaults to all variables in the data.

\item[\code{FUN}] an optional summary function or a list of summary functions
to be applied to group-varying variables, when collapsing the data
by groups.  Group-invariant variables are always summarized by the
unique value that they assume within that group. If \code{FUN} is a
single function it will be applied to each non-invariant variable by
group to produce the summary for that variable.  If \code{FUN} is a
list of functions, the names in the list should designate classes of
variables in the frame such as \code{ordered}, \code{factor}, or
\code{numeric}.  The indicated function will be applied to any
group-varying variables of that class.  The default functions to be
used are \code{mean} for numeric factors, and \code{Mode} for both
\code{factor} and \code{ordered}.  The \code{Mode} function, defined
internally in \code{gsummary}, returns the modal or most popular
value of the variable.  It is different from the \code{mode} function
that returns the S-language mode of the variable.

\item[\code{omitGroupingFactor}] an optional logical value.  When \code{TRUE}
the grouping factor itself will be omitted from the group-wise
summary of \code{data} but the levels of the grouping factor will
continue to be used as the row names for the returned data frame.
Defaults to \code{FALSE}.

\item[\code{...}] some methods for this generic require additional
arguments.  None are used in this method.
\end{ldescription}
\end{Arguments}
\begin{Value}
a data frame inheriting from class \code{coef.lmList} with the estimated
coefficients for each \code{lm} component of \code{object} and,
optionally, other covariates summarized over the groups corresponding
to the \code{lm} components. The returned object also inherits from
classes \code{ranef.lmList} and \code{data.frame}.\end{Value}
\begin{Author}\relax
Jose Pinheiro \email{Jose.Pinheiro@pharma.novartis.com} and Douglas Bates \email{bates@stat.wisc.edu}\end{Author}
\begin{SeeAlso}\relax
\code{\Link{lmList}}, \code{\Link{fixed.effects.lmList}},
\code{\Link{ranef.lmList}},
\code{\Link{plot.ranef.lmList}}, \code{\Link{gsummary}}\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
data(Orthodont)
fm1 <- lmList(distance ~ age|Subject, data = Orthodont)
coef(fm1)
coef(fm1, augFrame = TRUE)
\end{ExampleCode}
\end{Examples}

